Swift：macOSのシステムサウンドを鳴らす

macOSプリセットのシステムサウンドを鳴らす処理は非常に簡単に実装可能です．
Mojave時点で14種類の音を再生可能なようです．
サウンドファイルの実体が置いてある場所
/System/Library/Sounds/

NSSound

NSSound(named: "Basso")?.play()
NSSound(named: "Blow")?.play()
NSSound(named: "Bottle")?.play()
NSSound(named: "Frog")?.play()
NSSound(named: "Funk")?.play()
NSSound(named: "Glass")?.play()
NSSound(named: "Hero")?.play()
NSSound(named: "Morse")?.play()
NSSound(named: "Ping")?.play()
NSSound(named: "Pop")?.play()
NSSound(named: "Purr")?.play()
NSSound(named: "Sosumi")?.play()
NSSound(named: "Submarine")?.play()
NSSound(named: "Tink")?.play()

なお，音量はシステムの音量に依存します．